Piston construction



March 2, 1948. J, c, VROMAN PISTON CONSTRUCTION Filed June 10, 1945 FIGJ.

FIG.3.

' FIG.4.

INVENTOR. JOHNCVROMAN ATTO R N EYS .G G H v A M i TL Q a y v//v7/?Z///// Patented Mar. 2, 19 48 UNITED STATES oFFicE;

Claims. 1

I This invention relates to pumps and more particularly to constructions designed for use in oilwells. It is the object of the invention to obtain a construction which facilitates freeing of the plunger in, case it shouldat any time become stuck in the pump barrel.

It is the further. object to. obtain. various advantageous features. consists in the construction ashereinafter set forth.

In the. drawings:

Fig. 1 is an elevation of the pump plunger-within the barrel, which latter is in vertical central section;

Fig. 2 is a. vertical. central section through a portion of the plunger;

Fig. 3 is a perspective view of one of the packing rings;

Fig. 4 is a section on line'44, Fig. 2.

A is the pump barrel formed in the well casing and B is the pump plunger or piston within the barrel. C are packing rings sleeved on the plunger B and fitting the barrel to form a liquidtight seal therewith.

In the operation of oil wells it is sometimes necessary to temporarily stop'the pumping action and when this occurs there is danger that the packing on the plunger may become stuck in the barrel. Various devices have been heretofore constructed to efiect a freeing of the plunger but none of these constructions have been altogether satisfactory. I have, therefore, devised the following construction.

The plunger B is of the usual tubular type which carries a check valve B and is suitably connected to the operating rod. The upper portion D of the plunger fits the barrel A with only working clearance therebetween. Below the portion D is a tubular portion E of smaller diameter upon which the packing rings C are sleeved. These rings are preferably formed of annular members C, having an L-shaped cross section and with packing materials C engaging the small diameter portion thereof to extend radially outward to a slightly greater diameter and to also extend axially slightly beyond the end of said member C. The members C are internally of a polygonal form, which will fit over the tube E, but will contact therewith only at spaced points. This facilitates the removal of' the rings from the tube E whenever this is necessary and avoids the danger of sticking through corrosion.

Abutting against the upper end of the series of rings C is a member F sleeved on the tube E To this end, the invention.

2. nd lay n a. po ion. f? ma l i meter W hi h rranged. n. heiii e ad acent to he mbe is secured thereto as will be hereinafter scri d; h e te q e. hin t mem:

ber of suiiicient length to. receive a helical:

spring H. one end of which abuts against the up 9 Q t ember. Wh l i s. pposite n a ut-s g inst a sh u d r P- n. t e m e (5; V Above the shoulder C is an annular recess G which forms a chamber in which air is trapped. Th s. hamb r is e e y r zm a. n nelb iween he dia n en o h m s a d; and o th ee q it tub E therebetween. At the lower end of the series of-packing rings C is a member J threadedly engaging the lower end of the tube E and tightened against a shoulder thereof. This will place the helical spring H under compression. The rings C will be clamped between the members G and J so as to be normally in fixed position on the plunger.

With the construction as above described, when the plunger B is raised and lowered within the barrel A the rings C will form a liquid-tight seal thereb-etween. If, however, these rings should at any time stick to the barrel A during an interval in which the pump is not in operation, then the initial downward movement of the plunger will compress the helical spring H until the lower end of the member G strikes against the shoulder F of the member F. The impact thus produced will tend to loosen the rings C from the barrel and after a certain number of such impacts they will be freed so as to resume normal functioning. An essential part of this construction isthe air chamber formed by the counterbores G and G As this is sealed at its upper end, it is impossible to displace the air by the oil but it may be compressed to attain the same pressure as that'on the oil and thus, will not interfere with the relative movement of the members G and F and the delivery of the impact. If it were not for this air seal oil would fill the counterbores surrounding the spring H and as liquid is incompressible this would prevent relative movements of the members G and F.

What I claim as my invention is:

1. In a pump, the combination with a barrel and a plunger for reciprocation therewithin, of a series of packing rings sleeved on said plunger and forming peripheral sealing contact with said barrel, resilient means normally holding said series of rings in fixed relation to said plunger but permitting independent axial movement of the n ages an angular e e s. r ount rbor Wi h n. a mem r 6-, he. t r. mber of said series, an abutment for the opposite end of said series sleeved on said plunger to be axially movable thereon, a member secured to said plunger forming an air chamber within which said last mentioned abutment is movable, and resilient means for normally holding said abutment in fixed position on said plunger.

3. In a pump, the combination with a barrel and a plunger for reciprocation therewithin, of a series of packing rings sleeved on said plunger.

and having peripheral sealing contact with said barrel, a fixed abutment on said plunger engaging the lower end of said series, a movable abutment contacting the upper end of the series, a member above said movable abutment secured to said plunger and forming a trapped air chamber within which said movable abutment is displaceable, and resilient means within said chamber for normally holding said abutment against displacement.

4. In a pump, in combination with a barrel and a plunger for reciprocation therewithin, of a series of packing rings sleeved upon said plunger and forming peripheral sealing contact with said barrel, a fixed abutment on said plunger engaging the lower end of said series, a movable abutment on said plunger engaging the upper end of said a liances 4 series, said movable abutment having an upwardly extending shank of reduced diameter, a member on said plunger above said movable abutment chambered to receive said shank and to hold trapped air, and a helical spring within said chamber for normally holding said movable abutment in fixed position on said plunger.

5. In a pump, the combination with a barrel and a plunger for reciprocation therewithin, of a series of packing ringssleeved on said plunger and forming peripheralsealing contact with said barrel, a fixed abutment on said plunger engaging the lower end of said series, a movable abut-- ment on said plunger engaging the upper end of said series and having a shank of reduced diam- 1 eter extending upward therefrom, a member above said movable abutment having as its upper end a sealing joint with said plunger, and an annular recess therebeneath forming a trapped air chamber within which said shank extends, and a helical spring within said chamber bearing against said shank and normally holding the same in fixed position on said plunger.

JOHN C. VROMAN.

REFERENCES CITED- The following references are of record in the file of this patent:

UNITED STATES PATENTS 

